Have you noticed how when people are together they tend to mimic each other's behaviour - how when one person looks worried, the other will look worried; or how when one person laughs, the other will laugh. In some cases people will even sub-consciously mimic the physical position of the other person; crossing their legs, folding their arms or even leaning forwards and backwards and the same time as the other person. You have probably experienced it many times yourself when you have yawned for no reason other than because the person you are speaking to yawned.

Some scientists believe that this mimicking behaviour is caused by specialist brain cells called "mirror neurons". While others question the existence of such cells there is agreement that physically mimicking another person can help reproduce a similar psychological situation and therefore improve the degree to which both people can empathise with one another.

Here's an experiment you can do for yourself: Next time you are talking to a friend, just smile for no particular reason. The likelihood is that their first reaction will be to smile also. Only then will they ask you what you were smiling at.

The reason for this is that just as feeling happy can make you smile; smiling can also make you feel happy. This is because the physical act of smiling causes your body to release endorphins, which are compounds that create a feeling of well-being and happiness. By mimicking your smile your friend is therefore getting a sense of what you are feeling.

However, not everyone is as good at this as others. In a recent study, Dutch psychologists Mariëlle Stel and Ad van Leiden found that women are better at mimicking than men. In their tests they showed a series of photographs of faces to participants. Each photograph was displayed for only a tenth of a second and the participant was then asked to identify whether the subject in the photograph was displaying positive or negative emotions. For half of the trial participants were asked to clench their teeth, as this hindered their ability to mirror the facial expressions shown in the photographs.

The investigators measured how quickly participants responded to each face and found that when women were free to mimic the emotional expressions, they were faster than the men at recognising whether the expression was positive or negative. However, when mimicry was constrained, the men's performance was unchanged but the women's performance fell to the same level as the men.

The conclusion was that while both men and women use mimicking behaviour, women appear to do so more than men. Since other studies have demonstrated how women tend to have a greater disposition to empathise with others, possibly this study goes some way to showing how. It may also provide a clue as to why it is perceived that men are better at hiding their feelings.

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